The Hypertension Incidence Project involved the administration of a hypertension screening questionnaire to 3313 persons sampled from those found to be normotensive with no anti-hypertensive medication history in 1973 by the Hypertension Detection and Follow-up Program (HDFP). From this sample, a smaller sample of incident cases and matched controls will be given in-clinic physical examinations and interviews. The objective of the proposed study is to identify the incident cases of hypertension in a previously screened urban black population. The purpose of identifying these cases is to: a. Estimate the incidence of hypertension for the time interval 1973-1976. b. Describe the epidemiologic characteristics associated with this incidence. c. Search for differences in various exposure factors between the incident cases and suitably matched normotensive controls. We are approximately 68% through our preliminary screening phase with an interview completion rate of 84%. We have so far found the overall (three year) incidence of hypertension to be 22.1 per thousand for males and 14.0 per thousand for females. Based on these incidence figures we expect to complete 160 in-clinic physical examinations and interviews for males and 140 for females. Based on the number of control eligible males and females we expect to complete 90 in-clinic physical examinations and interviews for males and 140 for females.